Hey David (and all others interested in this "other coaster set" question),
We have been giving it thought - really! We do read these lists (our fans are SO valuable to us - you'll never know!!) and take note of the great suggestions that are constantly popping up. Sorry if we aren't always quick to respond - or even quick to acknowledge "Yup... got it! Thanks for the idea!" It's part of the "we're just so crazy busy!!" part of being such a small company (oh for the staff and resources of a huge multinational game producing company....)
We currently have no real plans to make another Martian Coasters set. Yes, having a "reversed image" set (with the Rainbow colors in the arrows and the Xeno colors in the squares) would be way cool - but it's just not going to happen in the foreseeable future. And thanks for the offer of volunteer help - but really, it's just easier to do in house.
We also need to see how the sales of Martian Coasters go. I know that if we were to sell out of every Coaster in the warehouse (and the Treehouse sets needed to play as well...) by next week, then we'd definitely look at what we'd like to do for our second print run. But looking at the economics of things, it really won't be feasible for us to do another (and as you say, smaller) print run of the "reversed image" coasters just by itself. If we ever do consider doing it - and no promises there - it would only be in conjunction with a reprint of the original set. Even that will be more expensive than just doing a reprint.
I hope that answers all the lingering questions. Please know that we LOVE our enthusiastic Rabbits who love our games so much that they want more/new/better/changes/tweaks to stuff!! It's what drives us to continue to do what we do!